全文获取类型
收费全文 | 1504114篇 |
免费 | 118628篇 |
国内免费 | 15488篇 |
专业分类
耳鼻咽喉 | 18359篇 |
儿科学 | 45394篇 |
妇产科学 | 38614篇 |
基础医学 | 218012篇 |
口腔科学 | 38965篇 |
临床医学 | 152255篇 |
内科学 | 282129篇 |
皮肤病学 | 28420篇 |
神经病学 | 120641篇 |
特种医学 | 54374篇 |
外国民族医学 | 463篇 |
外科学 | 201309篇 |
综合类 | 57675篇 |
现状与发展 | 40篇 |
一般理论 | 481篇 |
预防医学 | 125616篇 |
眼科学 | 33530篇 |
药学 | 117585篇 |
192篇 | |
中国医学 | 13961篇 |
肿瘤学 | 90215篇 |
出版年
2021年 | 20402篇 |
2020年 | 14000篇 |
2019年 | 17707篇 |
2018年 | 22644篇 |
2017年 | 18165篇 |
2016年 | 18698篇 |
2015年 | 23638篇 |
2014年 | 31045篇 |
2013年 | 41467篇 |
2012年 | 57896篇 |
2011年 | 61687篇 |
2010年 | 36580篇 |
2009年 | 32189篇 |
2008年 | 52297篇 |
2007年 | 54085篇 |
2006年 | 53877篇 |
2005年 | 52107篇 |
2004年 | 46937篇 |
2003年 | 44367篇 |
2002年 | 42343篇 |
2001年 | 63943篇 |
2000年 | 65778篇 |
1999年 | 55739篇 |
1998年 | 16728篇 |
1997年 | 15496篇 |
1996年 | 14816篇 |
1995年 | 14135篇 |
1994年 | 13079篇 |
1993年 | 11783篇 |
1992年 | 42678篇 |
1991年 | 41707篇 |
1990年 | 40219篇 |
1989年 | 38044篇 |
1988年 | 35206篇 |
1987年 | 34172篇 |
1986年 | 32514篇 |
1985年 | 30954篇 |
1984年 | 23182篇 |
1983年 | 19705篇 |
1982年 | 11820篇 |
1979年 | 20896篇 |
1978年 | 14855篇 |
1977年 | 12106篇 |
1976年 | 11911篇 |
1975年 | 12136篇 |
1974年 | 14837篇 |
1973年 | 14493篇 |
1972年 | 13371篇 |
1971年 | 12435篇 |
1970年 | 11500篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
992.
Cocaine-treated rats acquired a preference for cocaine-associated contextual stimuli (CS) relative to saline-injected control rats. However, when animals were given repeated tests for conditioned place preference intermittent between conditioning trials, they displayed an attenuation in strength of conditioning. This attenuation was not due to pharmacologic tolerance (Experiment 1), but rather reflected a disruption in learning due to exposure to the CS alone (Experiment 2). Like other examples of classical conditioning, the strength of the conditioned response (CR) as assessed by the conditioned place preference model may be influenced by partial reinforcement. 相似文献
993.
Forty patients suffering from asthmatic conditions, often accompanied by emphysema, were treated either with an extempore combination of salbutamol syrup plus 30-mg oxatomide tablets or with 30-mg oxatomide tablets alone for purposes of comparison. Greater efficacy was obtained with the combination, which produced positive results in terms of improved respiratory status, remission of clinical symptoms and reduced anti-asthma drug requirements in 90% of the cases treated, as against only 55% of satisfactory results obtained with oxatomide alone. The combination was very well tolerated with no incidence of adverse reactions, while the treatment with oxatomide alone, though on the whole well tolerated, gave rise to mild drowsiness in four cases. 相似文献
994.
Western transfer and immunoenzymatic staining with affinity-purified monospecific antiserum was used to detect a 38-Kd protein that bound to native and denatured DNA cellulose. This protein has previously been shown to be a delayed early herpes simplex virus type-2 specific protein. 相似文献
995.
The Brief Symptom Inventory (BSI), a 53-item psychiatric symptom checklist, was administered to 57 alcoholic inpatients on days 2, 10, 18 and 26 of their 28-day stay in an alcoholism rehabilitation unit at a Veterans Administration hospital. The results of the test show a steady decline in the patients' psychiatric symptomatology from week 1 to week 4 with the most dramatic improvement evidenced between weeks 1 and 2. 相似文献
996.
R W Wulkan L Zwang T L Liem B G Blijenberg B Leijnse 《Zeitschrift für klinische Chemie und klinische Biochemie》1987,25(10):719-722
An expert system for evaluation of X-ray diffraction patterns of urinary calculi is described and evaluated. The software was developed using the PERSONAL CONSULTANT expert system shell from Texas Instruments. 相似文献
997.
Activity of newer beta-lactam agents against clinical isolates of Bacteroides fragilis and other Bacteroides species. 总被引:7,自引:4,他引:3
下载免费PDF全文
![点击此处可从《Antimicrobial agents and chemotherapy》网站下载免费的PDF全文](/ch/ext_images/free.gif)
J P O''''Keefe F R Venezio C A DiVincenzo K L Shatzer 《Antimicrobial agents and chemotherapy》1987,31(12):2002-2004
The in vitro activities of beta-lactam antibiotics against Bacteroides fragilis and B. fragilis group isolates are presented. Clinical isolates from 1986 were compared with strains from 1979 to 1982. Imipenem, ticarcillin-clavulanic acid, and ceftizoxime were the most active agents. Cefotetan was equivalent to cefoxitin against B. fragilis but less active against B. fragilis group isolates. Enhancement of cefotaxime by its desacetyl metabolite was minimal. 相似文献
998.
999.
目的探讨儿童过敏性紫癜的影像学特点及其临床价值。方法回顾性分析32例过敏性紫癜并发肠套叠患儿的临床及影像学资料。结果出现并发症之前过敏性紫癜的腹部X线主要表现为局限性小肠充气扩张,粘膜增粗,肠间隙增宽,可伴有液平;B超显示为不同程度的多发节段性肠壁水肿增厚,肠管狭窄等表现;出现并发症后,其X线表现加重,部分病例伴有肠穿孔;B超及X线监视下空气灌肠可以明确是否并发肠套叠,部分病例可通过空气灌肠达到复位治疗的目的。结论影像学检查的重要临床价值在于能与需要手术治疗的其他急腹症相鉴别,同时可以了解其是否并发常见的并发症,为临床确定治疗方案提供可靠的信息。 相似文献
1000.
Patients with Fabry disease on dialysis in the United States. 总被引:9,自引:0,他引:9
Ravi Thadhani Myles Wolf Michael L West Marcello Tonelli Robin Ruthazer Gregory M Pastores Gregorio T Obrador 《Kidney international》2002,61(1):249-255
BACKGROUND.: Fabry disease results from an X-linked deficiency of lysosomal alpha-galactosidase A and is a rare cause of end-stage renal disease. Little is known about the characteristics of patients with Fabry disease that initiate dialysis in the United States, although data from Europe suggests these individuals have a poor survival. METHODS.: Using the United States Renal Disease System database, we first studied in detail 42 Fabry patients who initiated dialysis between April 1995 (following the introduction of the new detailed HCFA 2728 form) and July 1998. To examine crude survival in a larger cohort, 95 Fabry patients were studied who initiated dialysis between 1985 and 1993, similar to the European Registry. Diabetic and non-diabetic controls matched by age, gender, race, year of dialysis initiation, and initial dialysis modality were examined for comparison. RESULTS.: During the years 1995 to 1998, the mean age of Fabry patients that initiated dialysis was 42 years, 83% were Caucasian, and 10% were African American. Despite the X-linked inheritance of Fabry disease, 12% of Fabry patients on dialysis were female. At initiation of dialysis mean serum albumin and creatinine were significantly higher and mean body mass index was significantly lower among Fabry patients, but mean glomerular filtration rate was similar to controls. Fabry patients tended to have a lower three-year survival compared to non-diabetic controls, but the results were not significantly different. In a larger cohort of Fabry patients who initiated dialysis between 1985 and 1993, the three-year survival of Fabry patients was significantly lower than non-diabetic controls: 63% (95% CI, 50 to 75%) versus 74% (95% CI, 67 to 80%; P=0.03). CONCLUSION.: End-stage renal disease is associated with significant morbidity and mortality among patients with Fabry disease. Recent evidence that progression of Fabry disease may be attenuated by enzyme replacement therapy necessitates increased awareness of Fabry disease and its comorbidities. 相似文献